This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 2 |
| 3 | -2 |
| 4 | 3 |
| 5 | -2 |
| 6 | 1 |
| 7 | 4 |
| 8 | -10 |
| 9 | 22 |
| 10 | -36 |
| 11 | 56 |
| 12 | -72 |
| 13 | 84 |
| 14 | -71 |
| 15 | 22 |
| 16 | 99 |
| 17 | -311 |
| 18 | 654 |
| 19 | -1122 |
| 20 | 1702 |
| 21 | -2267 |
| 22 | 2611 |
| 23 | -2312 |
| 24 | 795 |
| 25 | 2789 |
| 26 | -9352 |
| 27 | 19802 |
| 28 | -34442 |
| 29 | 52436 |
| 30 | -70521 |
| 31 | 81869 |
| 32 | -74248 |
| 33 | 29099 |
| 34 | 79012 |
| 35 | -279732 |
| 36 | 600894 |
| 37 | -1054809 |
| 38 | 1616669 |
| 39 | -2190772 |
| 40 | 2567994 |